Method of forming multicolor aluminum alloy

ABSTRACT

A method for forming multicolor aluminum alloy has steps of preparing, surface treating, forming, processing and reprocessing. Preparing comprises providing an aluminum alloy substrate and cleaning with water. Surface treating has disposing the substrate in a base electrolytic solution to form a base oxide layer by anodizing. Forming has forming a membrane of transparent, acid-proof, insulated plastic on the substrate. Processing has removing local area membrane and corresponding oxide layer from the substrate and cleaning. Reprocessing has disposing the clean substrate in a subsequent electrolytic solution to form a subsequent oxide layer on areas of the substrate exposed by the membrane by anodizing.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of forming a multicolor aluminum alloy, and more particularly to a method of forming a multicolor aluminum alloy by anodizing for preferred color quality.

2. Description of the Prior Arts

A conventional anodizing surface treatment comprises forming a base oxide layer on a metal substrate by chemical or electrochemical treatment to provide a protective effect to the metal substrate. The metal may be aluminum alloy. The conventional anodizing surface treatment may further comprise steps of forming a base ink layer on the base oxide layer, forming a subsequent oxide layer and forming a subsequent ink layer on the subsequent oxide layer, wherein the steps after reforming the surface of the base layers may be repeated and the subsequent layer is included as the base in such repeated treatments to provide a multicolor effect.

However, the step of reforming the surface of the base layer requires a cutting or a milling process to expose the substrate such as cutting or milling, which uses coolant and oil that must be fully removed, or the coolant and oil prevent the surface oxide layer being formed on the substrate.

In addition, cutting or milling may damage the original ink layer. The step of forming the surface oxide layer may cause the original oxide layer to flake, thereby allowing the metal substrate to be oxidized.

Furthermore, the surface ink layer may bleed into the base ink layer. The base ink layer must also be fully removed before a surface oxide layer can be formed on the substrate so increasing a manufacturing time of the multicolor substrate.

To overcome the shortcomings, the present invention provides a method of forming multicolor on aluminum alloy to mitigate or obviate the aforementioned problems.

SUMMARY OF THE INVENTION

The main objective of the present invention is to provide a method of forming multicolor aluminum alloy, and more particularly to a method of forming multicolor aluminum alloy using anodizing surface treatment for preferred color quality.

A method for forming multicolor aluminum alloy comprising steps of preparing, surface treating, forming, processing and reprocessing. Preparing comprises providing an aluminum alloy substrate and cleaning with water. Surface treating comprises disposing the substrate in a base electrolytic solution to form a base oxide layer by anodizing. Forming comprises forming a membrane of transparent, acid-proof, insulated plastic on the substrate. Processing comprises removing local area membrane and corresponding oxide layer from the substrate and cleaning. Reprocessing comprises disposing the clean substrate in a subsequent electrolytic solution to form a subsequent oxide layer on areas of the substrate exposed by the membrane by anodizing.

Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a method of forming multicolor aluminum alloy in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIG. 1, a method of forming multicolor aluminum alloy in accordance with the present invention comprises steps of preparing, surface treating, forming, processing and reprocessing.

The step of preparing comprises acts of providing an aluminum alloy substrate having an external surface, machining the substrate to form a shaped substrate by a Computer Numerical Control (CNC) machine with coolant and oil, removing the coolant and oil from the external surface with sodium hydroxide and cleaning the shaped substrate with water, thereby removing impurities from the external surface of the substrate to provide a clean external surface.

The step of surface treatment comprises disposing the substrate with clean external surface in a base electrolytic solution to form a colored oxide layer on the substrate by an anodizing surface treatment, removing the substrate from the base electrolytic solution after forming the base oxide layer on the external surface of the substrate and drying to form a colored substrate.

The step of forming comprises forming a membrane on the colored oxide layer using a transparent acid-proof insulated plastic.

The step of processing comprises processing the substrate to remove at least one local area of membrane and corresponding local area of colored oxide layer from the external surface of the colored substrate with coolant and oil using the CNC machine, removing the coolant and oil from the colored substrate using sodium hydroxide and cleaning the external surface of the substrate with water, thereby removing impurities from and providing a clean colored substrate.

The step of reprocessing comprises disposing the substrate in a subsequent electrolytic solution to form a subsequent oxide layer on the external surface of the substrate exposed by the membrane, and removing the substrate from the subsequent electrolytic solution after forming the subsequent oxide layer on the external surface of the substrate and drying to add a color to the colored oxide layer.

By forming a transparent, acid-proof, insulating plastic to cover and protect the colored oxide, the coolant and oil in subsequent steps do not adhere to the colored oxide layer so is cleaned easily. When the local membrane on the local colored oxide is removed, the local colored oxide is fully replaced by the oxide layer so bleeding does not occur and damage to the oxide layer is replaced with the colored layer. Therefore, a preferred color quality is achieved.

Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and features of the invention, the disclosure is illustrative only. Changes may be made in the details, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. 

1. A method of forming multicolor aluminum alloy comprising steps of: preparing, comprising providing an aluminum alloy substrate having an external surface; machining the substrate with coolant and oil to form a shaped substrate; removing the coolant and oil from the external surface of the substrate; and cleaning the shaped substrate with water; surface treating, comprising disposing the shaped substrate with clean external surface in a base electrolytic solution to form a base oxide layer on the external surface of the substrate by an anodizing surface treatment to provide a colored substrate: forming, comprising forming a membrane on the colored substrate by a transparent, acid-proof, insulating plastic; processing, comprising processing the colored substrate to remove at least one local area of membrane and corresponding local area of colored oxide layer from the external surface of the colored substrate; removing the coolant and oil from the colored substrate; and cleaning the external surface of the colored substrate with water to form a clean colored substrate; and reprocessing, comprising disposing the clean colored substrate in a subsequent electrolytic solution to from a subsequent oxide layer on the external surface of the substrate exposed by the membrane.
 2. The method as claimed in claim 1, wherein the step of surface treating further comprises removing the substrate from the base electrolytic solution after forming the base oxide layer on the external surface of substrate and drying.
 3. The method as claimed in claim 2, wherein the reprocessing step further comprises removing the substrate from the subsequent electrolytic solution after forming the subsequent oxide layer on the external surface of the substrate and drying.
 4. The method as claimed in claim 3, wherein the step of machining the substrate is performed by a Computer Numerical Control (CNC) machine.
 5. The method as claimed in claim 4, wherein the step of processing the substrate to remove at least one local area membrane and corresponding local area of colored oxide layer from the external surface of the colored substrate is performed by the CNC machine.
 6. The method as claimed in claim 5, wherein in the steps of removing the coolant and oil uses sodium hydroxide.
 7. The method as claimed in claim 1, wherein the steps of surface treating and surface reprocessing further comprise removing the substrate from the electrolytic solution after forming the oxide layer and drying.
 8. The method as claimed in claim 1, wherein in the step of machining the substrate to form the shaped substrate is performed by a CNC machine.
 9. The method as claimed in claim 1, wherein the step of processing the substrate to remove at least one local area membrane and corresponding local area of colored oxide layer from the external surface of the colored substrate is performed by a CNC machine.
 10. The method as claimed in claim 1, wherein the steps of removing the coolant and oil form the external surface of the substrate uses sodium hydroxide. 